Various techniques have been reported for monitoring growth or other characteristics of biological cells. One such technique involves the use of impedance methods, as reported by Lind R et. al. in “Single Cell Mobility and Adhesion Monitoring Using Extracellular Electrodes”, Biosensors and Bioelectronics, 6 (4), pp 359-367, 1991. Other reported techniques involve determining changes in impedance and linking these to cell or bacterial growth or movement.
Most of these techniques involve measuring ac impedance of cells or bacteria in their appropriate growth media. A good degree of success has been achieved in using these methods to link overall changes in impedance, Z, at some fixed electrical stimulating frequency, typically in the kilohertz range, to the growth of cells and bacteria. However, the use of impedance techniques for monitoring growth or other characteristics of biological cells is complicated by the fact that each measuring system has its own characteristic impedance, which must be separated from the impedance response of the cells.